Effects of experimental conditions on the release of 45calcium from prelabeled fetal mouse long bones

• Published in: Bone (New York, N.Y.) Vol. 17; no. 1; pp. 63 - 69
• Main Authors: VAN BEEK, E, OOSTENDORP-VAN DE RUIT, M, VAN DER WEE-PALS, L, BLOYS, H, VAN DE BENT, C, PAPAPOULOS, S, LÖWIK, C
• Format: Conference Proceeding Journal Article
• Language: English
• Published: New York, NY Elsevier Science 01.07.1995
• Subjects: Acid Phosphatase - metabolism; Animals; Biological and medical sciences; Bone Marrow Cells; Bone Resorption - diagnosis; Bone Resorption - drug therapy; Bone Resorption - pathology; Bone Resorption - physiopathology; Calcium - metabolism; Calcium Radioisotopes; Cells, Cultured; Culture Techniques; Diphosphonates - pharmacology; Dose-Response Relationship, Drug; Fundamental and applied biological sciences. Psychology; Growth Inhibitors - pharmacology; Interleukin-6; Isoenzymes - metabolism; Leukemia Inhibitory Factor; Lymphokines - pharmacology; Metacarpus - drug effects; Metacarpus - embryology; Metacarpus - metabolism; Metatarsal Bones - drug effects; Metatarsal Bones - embryology; Metatarsal Bones - metabolism; Mice; Osteoclasts - cytology; Parathyroid Hormone - pharmacology; Radius - drug effects; Radius - embryology; Radius - metabolism; Skeleton and joints; Stromal Cells - cytology; Tartrate-Resistant Acid Phosphatase; Ulna - drug effects; Ulna - embryology; Ulna - metabolism; Vertebrates: osteoarticular system, musculoskeletal system; Cell culture; Calcium; Rodentia; Biological marker; Resorption; Osteoclast; Inorganic element; In vitro; Osteoarticular system; Vertebrata; Mammalia; Mouse; Newborn animal; Fetus; Models; Long bone
• ISSN: 8756-3282; 1873-2763
• DOI: 10.1016/8756-3282(95)00135-Z

Embryonic/neonatal bones in culture are commonly used for the study of osteoclastic resorption in vitro. For this purpose, the release of 45calcium (45Ca) from prelabeled bones is measured as an index of resorption. We studied 45Ca release from two types of long bone explants after different preparation methods: 17-day-old fetal mouse radii/ulnae with and without cartilage ends (intact radii/ulnae and shafts, respectively), and intact 18-day old metacarpals/metatarsals. In addition, we examined the effect of different culture conditions, such as cultures performed under the surface of the medium or at the interphase of medium and air, on 45Ca release and histology. When intact radii/ulnae were cultured under the surface of the medium, there was always a significant amount (10%) of net basal 45Ca release (corrected for physicochemical exchange) that was not due to osteoclastic resorption, as it could not be suppressed by inhibitors of resorption even at high concentrations. Moreover, histologically TRAcP-positive cells were almost absent after culture and the bone marrow/stromal cells in the center of the bone appeared necrotic, possibly due to a lack of oxygen. Under these culture conditions, osteoclasts could survive in shafts as well as in PTH-stimulated intact radii/ulnae, but a constant amount of 10% 45Ca, not due to resorption, was still released in the medium. When these explants were cultured at the interphase of medium and air, basal and stimulated 45Ca release originated from osteoclastic resorption. In contrast, in 18-day-old fetal mouse metacarpals/metatarsals, the experimental conditions applied did not affect 45Ca release, which was always due to resorption of the explants by osteoclasts.